# Hey julians. I found this one a little tricky to fix. I have a rosenbrock function

Hey julians. I found this one a little tricky to fix. I have a rosenbrock function that takes 2 values and returns 1 value. So I was trying to run this as a comprehension, but I am getting out a (401,401) array, instead of a (401,1) array. Here is the code.

``````x = -2:0.01:2
y = -2:0.01:2
rosenbrock(x,p) =  (p - x)^2 + p * (x - x^2)^2
z = [rosenbrock([i, j], p) for i=x, j=y]
``````

But I keep getting out a (401,401) array instead of a 401,1 array. Now it makes sense that the comprehension is iterating over the `i` and `j` dimensions, so there are probably repeated entries. But still I was not clear on how to fix this. I tried parenthesis `(i=x, j=y)`.

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(Original message ) (More Info)

Is it what you want ?

``````z = [rosenbrock([ij...], p) for ij ∈ zip(x,y)]
``````
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